Authorities in Chengdu, Sichuan province, are looking into food safety incidents at a local primary school after parents posted videos and photos on Tuesday of moldy food, including tomatoes, meat pies and rotten frozen meat in school canteens.

Some parents at the primary school affiliated to Chengdu No 7 High School Development School said their children had diarrhea and blood in their stool after eating at the school canteen.

Chengdu No 7 High School Development School has a primary school, middle school, high school and international school, with 140 classes and more than 6,000 students and teachers, according to its website.

The school canteen has been outsourced to Sichuan Deyu Logistics Management Service Co, according to the website Shangyou News. The company's website was down on Wednesday.

The public security bureau of Wenjiang district in Chengdu, where the school is located, is looking into eight school administrators in connection with the incident, the information office of the Wenjiang district government said on Wednesday.

The district's market regulation bureau has taken samples of 19 batches of food and sealed up all food at the storeroom and freezer, they said.

The school has ended its relations with its food supplier and will look for a new food supplier under the supervision of parents and authorities, the statements said.

The city's education authority and Chengdu Administration of Market Regulation have sent work groups to look into the incidents and will publish the results as soon as possible, they said.

"The district government has zero tolerance for food safety incidents and will hold violators responsible, no matter who they are," they added.

Similar scandals have happened in other parts of the country. In October, the head of a well-known international school in Shanghai was dismissed after health and education authorities confirmed the discovery of moldy tomatoes and onions in a kitchen that prepared food for pupils.

Located in the Pudong area, SMIC Private School is a K-12 school funded by China's largest semiconductor producer, Semiconductor Manufacturing International Corporation. It recruits pupils from families of its own workforce as well as from outside the company, and charges tuition fees as high as 120,000 yuan ($17,800) a year.

The food supplier, identified by the health authorities as Shanghai Eurest Food Technologies Service Company, is wholly-owned by the UK-based Compass Group, a global catering service provider.

In response to the problems, the Ministry of Education issued a notice on Monday that people in charge of kindergartens, primary and secondary schools in China should eat with students at school canteens to strengthen the safety of campus food. The notice will take effect on April 1.